User equipment and communication method

ABSTRACT

A user equipment includes a transmitting unit that transmits a measurement result of a secondary cell; a receiving unit that receives a signal to activate the secondary cell; and a control unit that uses previously obtained information of the secondary cell to activate the secondary cell when a predetermined condition associated with a power class of the user equipment is satisfied.

TECHNICAL FIELD

The present invention relates to a user equipment and a communicationmethod in a radio communication system.

BACKGROUND ART

In regard to the New Radio (NR), in order to secure coverage forcommunication using radio waves in a high frequency band, beamforming isapplied to transmission of data on a Physical Downlink Shared Channel(PDSCH), transmission of a control signal on a Physical Downlink ControlChannel (PDCCH), transmission of a synchronization signal and broadcastinformation on a Synchronization Signal/Physical Broadcast Channel(SS/PBCH) Block (SSB), and transmission of a reference signal (ChannelState Information Reference Signal (CSI-RS)/Demodulation ReferenceSignal (DMRS)).

Beam management or beam control is important for communication usingbeams. For example, if there are two beams, a base station is to signalto user equipment which beam is used to transmit a signal. ATransmission Configuration Indication (TCI) state is specified to signalto user equipment a beam to be used or to signal to user equipmentswitching of a beam to be used.

RELATED ART DOCUMENT Non-Patent Document

Non-Patent Document 1: 3GPP TS 38.214 V15.5.0 (2019-03)

Non-Patent Document 2: 3GPP TS 38.321 V15.5.0 (2019-03)

Non-Patent Document 3: 3GPP TS 38.133 V15.5.0 (2019-03)

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

In NR, a plurality of Power Classes (PCs) is specified for a userequipment while assuming various use cases and related constraints(e.g., size, a number of antennas). PC1: Fixed wireless access (FWA) UE,PC2: Vehicular UE, PC3: Handheld UE, and PC4: High power non-handheldUE. There is a need for specifying, for each power class of the userequipment, a condition that specifies whether information on a secondarycell obtained in advance can be used for activation of the secondarycell.

Means for Solving the Problem

According to an aspect of the present invention, there is provided auser equipment including a transmitting unit that transmits ameasurement result of a secondary cell; a receiving unit that receives asignal to activate the secondary cell; and a control unit that usespreviously obtained information of the secondary cell to activate thesecondary cell when a predetermined condition associated with a powerclass of the user equipment is satisfied.

Advantage of the Invention

According to an embodiment, a technique is provided with which acondition can be defined per power class of the user equipment. Thecondition specifies whether information on a secondary cell obtained inadvance by a user equipment is to be used for activation of thesecondary cell.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a configuration diagram of a communication system according toan embodiment.

FIG. 2 is a diagram illustrating an example of types of QCL.

FIG. 3 is a diagram illustrating an example of an NR beam managementprocess.

FIG. 4 is a diagram illustrating an example of a TCI state configured inuser equipment.

FIG. 5 is a diagram illustrating an example of DC.

FIG. 6 is a diagram illustrating an example of DC.

FIG. 7 is a diagram illustrating an example of a functionalconfiguration of a user equipment.

FIG. 8 is a diagram illustrating an example of a functionalconfiguration of a base station.

FIG. 9 is a diagram illustrating an example of the hardwareconfiguration of the user equipment and the base station.

EMBODIMENTS OF THE INVENTION

In the following, embodiments of the present invention are describedwith reference to the drawings. The embodiments described below aremerely examples, and embodiments to which the present invention isapplied are not limited to the following embodiments.

In the embodiments of the present invention described below, terms usedin the existing LTE are used, such as Synchronization Signal (SS),Primary SS (PSS), Secondary SS (SSS), Physical Broadcast channel (PBCH),and Physical Random Access channel (PRACH). This is for convenience ofdescription, and signals and functions similar to these may be referredto by other names. The above-described terms in NR correspond to NR-SS,NR-PSS, NR-SSS, NR-PBCH, NR-PRACH, and the like. However, even if asignal is used for NR, the signal is not always explicitly indicated as“NR-.”

In embodiments of the present invention, a duplex method may be a TimeDivision Duplex (TDD) method, a Frequency Division Duplex (FDD) method,or any other method (e.g., Flexible Duplexing).

In the following description, a method of transmitting a signal using atransmit beam may be digital beamforming, in which a signal multipliedby a precoding vector (precoded with the precoding vector) istransmitted, or analog beamforming, in which beamforming is implementedusing a variable phase shifter in an RF (Radio Frequency) circuit.Similarly, a method of receiving a signal using a receiving beam may bedigital beamforming, in which a received signal is multiplied by apredetermined weight vector, or analog beamforming, in which beamformingis implemented using a variable phase shifter in an RF circuit. Hybridbeamforming combining digital beamforming and analog beamforming may beapplied to transmission and/or reception. Transmitting a signal using atransmit beam may be transmitting the signal with a specific antennaport. Similarly, receiving a signal using a receiving beam may bereceiving the signal with a specific antenna port. An antenna portrefers to a logical antenna port or a physical antenna port defined bythe 3GPP standard. The above-described precoding or beamforming may bereferred to as a precoder, a spatial domain filter, or the like.

Note that a method of forming a transmit beam and receiving beam is notlimited to the above-described methods. For example, in a base station10 or user equipment 20 having multiple antennas, a method of changingan angle of each antenna may be used, a method of using a precodingvector and a method of changing the angle of the antenna may be used, amethod of switching different antenna panels may be used, a method ofcombining multiple antenna panels may be used, or other methods may beused. For example, in a high frequency band, a plurality of mutuallydifferent transmit beams may be used. The use of multiple transmit beamsis called multi-beam operation, and the use of a single transmit beam iscalled single-beam operation.

In the embodiments of the present invention, “configuring” a radioparameter or the like may include pre-configuring a predetermined value,or configuring the radio parameter signalled from the base station 10 orthe user equipment 20.

FIG. 1 is a diagram illustrating a radio communication system accordingto an embodiment of the present invention. The radio communicationsystem in an embodiment of the present invention includes a base station10 and user equipment 20, as depicted in FIG. 1. In FIG. 1, one basestation 10 and one unit of the user equipment 20 are depicted. However,this is an example, and, for each of the devices, there may be aplurality of devices.

The base station 10 is a communication device that provides one or morecells and performs radio communication with the user equipment 20. Aphysical resource of a radio signal is defined in a time domain and afrequency domain, the time domain may be defined by a number of OFDMsymbols, and the frequency domain may be defined by a number ofsub-carriers or a number of resource blocks. The base station 10transmits a synchronization signal and system information to the userequipment 20. A synchronization signal is, for example, NR-PSS andNR-SSS. A part of system information is transmitted, for example, byNR-PBCH, which is also called broadcast information. A synchronizationsignal and broadcast information may be periodically transmitted as anSS block (SS/PBCH block) consisting of a predetermined number of OFDMsymbols. For example, the base station 10 transmits a control signal ordata in DL (Downlink) to the user equipment 20 and receives a controlsignal or data in UL (Uplink) from the user equipment 20. The basestation 10 and the user equipment 20 are capable of transmitting andreceiving signals while performing beamforming. For example, as shown inFIG. 1, a reference signal transmitted from the base station 10 includesa Channel State Information Reference Signal (CSI-RS), and a channeltransmitted from the base station 10 includes Physical Downlink ControlChannel (PDCCH) and Physical Downlink Shared Channel (PDSCH).

The user equipment 20 is a communication device provided with a radiocommunication function, such as a smartphone, a cellular phone, atablet, a wearable terminal, and a communication module forMachine-to-Machine (M2M). The user equipment 20 utilizes variouscommunication services provided by a radio communication system byreceiving a control signal or data in DL from the base station 10 andtransmitting a control signal or data in UL to the base station 10. Forexample, as illustrated in FIG. 1, channels transmitted from the userequipment 20 include Physical Uplink Control Channel (PUCCH) andPhysical Uplink Shared Channel (PUSCH).

In the New Radio (NR), in order to secure coverage for communicationsusing radio waves in a high frequency band, beamforming is applied totransmission of data in a Physical Downlink Shared Channel (PDSCH),transmission of a control signal in a Physical Downlink Control Channel(PDCCH), transmission of a synchronization signal and broadcastinformation in a Synchronization Signal/Physical Broadcast Channel(SS/PBCH) Block (SSB), and transmission of a reference signal (ChannelState Information Signal (CSI-RS)/Demodulation Reference Signal (DMRS)).

For example, in Frequency Range 2 (FR2), i.e., in a frequency band ofmillimeter wave greater than or equal to 24 GHz, 64 beams can be used,and in Frequency Range 1 (FR1), i.e., in a sub-6 GHz frequency band, 8beams can be used.

For performing communication using a beam, beam management or beamcontrol is important. For example, if there are two beams, the basestation 10 may need to signal to the user equipment 20 which beam isused to transmit the signal. A Transmission Configuration Indication(TCI) state is specified so as to transmit, to the user equipment 20, anotification of the beam to be used, or to transmit, to the userequipment 20, a notification of switching of a beam to be used.

Details to be signaled by a TCI state include Quasi-Co-Location (QCL)that indicates it is possible to assume that one reference signal (RS)and one channel are identical radio channels, or the one referencesignal (RS) and the one channel have the same radio property (the samebeam). QCL is specified in Non-Patent Document 1.

For example, the fact that a reference signal, such as a CSI-RS (orSS/PBCH) and a PDSCH that is a channel for transmitting data are QCLimplies that the reference signal and the data have a relationship suchthat the reference signal and the data are transmitted with a same beam.

As shown in FIG. 2, four types of QCL are defined from A to D. Forsignaling beam information, QCL Type D is mainly used. QCL Type Dimplies that transmissions by the same beam. Other than that, forexample, QCL Type A is used for signaling colocation, for example,whether the base stations 10 are located at a same location.

(Beam Management Function)

In NR, a beam management function is specified for selecting an optimumpair of a beam used by the base station 10 for transmission and a beamused by the user equipment for reception.

FIG. 3 is a diagram illustrating an example of NR beam managementprocessing. In step S101 of FIG. 3, the base station 10 signals, to theuser equipment 20, a configuration of a reference signal and aconfiguration of reporting. In step S102, the user equipment 20 measuresthe quality of a beam (RSRP: Reference Signal Received Power) using areference signal transmitted in the signaled resource, and the userequipment 20 transmits the measured quality to the base station 10.

The base station 10 calculates an optimum beam based on quality of eachbeam reported from the user equipment 20, and the base station 10signals, to the user equipment 20, information indicating that dataand/or a control signal is transmitted with the calculated beam, as aTCI state (step S103).

As a function that can be used in a beam management procedure, an RSresource configuration function, a Beam reporting function, and a Beamindication function are known, which are described below.

(RS Resource Configuration Function)

The RS resource configuration function is a function for configuring areference signal used for beam management (beam quality reporting: beamreporting/L1-RSRP reporting) by RRC signaling. Here, as a referencesignal used for beam quality reporting, SSB or CSI-RS can be configured.Furthermore, supported periodicities of a CSI-RS include, aperiodic,semi-persistent, and periodic. Furthermore, as a function of optimizingthe receiving beam (Rx beam) in the user equipment 20, repetition inwhich the base station 10 repeatedly transmits a CSI-RS with the samebeam, can be configured by RRC signaling (CSI-RS with repetition on oroff).

(Beam Reporting Function)

A Beam reporting function is a function for reporting beam quality usingthe framework of the CSI-RS report. The user equipment 20 reports beamquality to the base station 10. Supported reporting periodicitiesinclude, aperiodic, semi-persistent, and periodic.

(Beam Indication Function)

By the beam indication function, a Transmission ConfigurationIndication-state (TCI-state) can be configured, which is for signaling,from a network to the user equipment 20, information indicating thebeams to be used by the base station 10 for transmission of a referencesignal, data, and a control signal.

(TCI State Configuration Method/Switching Method)

FIG. 4 is a diagram illustrating an example of a TCI state configuredfor the user equipment 20.

By Radio Resource Control (RRC) signaling, up to 128 TCI states can beconfigured for PDSCH in the user equipment 20. Additionally, by RRCsignaling, up to 64 TCI states can be configured for PDCCH in the userequipment 20 (The TCI states for PDCCH are a subset of the TCI statesconfigured for PDSCH).

With respect to the TCI states for the PDCCH, it is possible to activateup to eight TCI states by a Medium Access Control Control Element (MACCE) out of the TCI states configured by the RRC signaling in the userequipment 20, and it is possible to deactivate the activated TCI state.The user equipment 20 monitors the active TCI state.

With respect to the TCI states for the PDSCH, it is possible to activateup to eight TCI states by the Medium Access Control Control Element (MACCE) out of the TCI states configured by the RRC signaling in the userequipment 20, and it is possible to deactivate the activated TCI state.Furthermore, the base station 10 can specify a TCI state of the PDSCH byDownlink Control Information (DCI) among the TCI states activated by theMAC CE. In this case, the user equipment 20 receives data transmitted byPDSCH assuming the TCI state designated by the DCI.

The operation of the user equipment 20 during switching of the TCI stateis currently discussed in RAN 4 of the 3GPP.

In Radio Resource Management (RRM) in RAN 4 of 3GPP, allowed time isspecified until completion of activation of a deactivated Secondary Cell(SCell) (Non-Patent Document 3).

Specifically, it is specified that the user equipment 20 shall be ableto send an accurate Channel State Information (CSI) report to a targetSCell x seconds after the user equipment 20 receives an SCell activationcommand at slot n.

Here, the-above described x seconds include the following times:

-   a time for the user equipment 20 to decode a Medium Access Control    (MAC) command received at the slot n;-   a time for detection of a Synchronization Signal (PSS)/a Secondary    Synchronization Signal (SSS) and time and frequency synchronization;    and-   a delay time related to a CSI report that occurs due to Channel    State Information (CSI)-Reference Signal (RS) receiving timing,    report transmission allowed timing, and so forth.

In the case of NR, the user equipment 20 receives Physical DownlinkShared Channel (PDSCH) and Physical Downlink Control Channel (PDCCH)based on information on a TCI state signaled from the base station 10.

Specifically, the base station 10 causes the user equipment 20 to reportLayer 1-Reference Signal Received power (L1-RSRP) based on aSynchronization Signal Block (SSB) and/or a CSI-RS, and the base station10 signals, to the user equipment 20, which SSB and/or CSI-RS is thesame radio channel with PDSCH and PDCCH (transmitted with the samebeam), as a Transmission Configuration Indication (TCI) state.

It is specified in Non-Patent Document 2 that L1-RSRP and CSI reportingoperations are not performed for a deactivated SCell (L1-RSRPmeasurement is a part of CSI reporting).

1>if the SCell is deactivated:

2>not transmit SRS on the SCell;

2>not report CSI for the SCell;

2>not transmit on UL-SCH on the SCell;

2>not transmit on RACH on the SCell;

2>not monitor the PDCCH on the SCell;

2>not monitor the PDCCH for the SCell;

2>not transmit PUCCH on the SCell.

Accordingly, at a moment at which a deactivated SCell is reactivated,L1-RSRP reporting from the user equipment 20 is not performed for theSCell. Thus, the base station 10 may be unable to determine which SSB orCSI-RS would be appropriate as a QCL resource (beam). As a result, theuser equipment 20 may be unable to transmit a CSI report in a properdirection.

Even if the SCell is deactivated, the user equipment 20 performs Layer 3(L3) measurement. Accordingly, it has been proposed to use a result ofthe L3 measurement in determining whether SSB or CSI-RS is appropriateas a QCL resource. However, this proposal has the following problems.

If L3 measurement is configured as event trigger reporting, the userequipment 20 does not report L3 measurement unless an event occurs.Accordingly, the base station 10 is unable to obtain an L3 measurementreport unless an event occurs.

In L3 measurement, a measurement result is calculated by averagingmeasurement results using multiple samples. Accordingly, a receivingbeam of the user equipment 20 that is determined to be optimal based onthe L3 measurement may differ from a receiving beam of the userequipment 20 that is determined to be optimal in the L1-RSRPmeasurement.

When the SCell is deactivated and re-activated, by clarifying acondition on a receiving beam that can be applied by the user equipment20, efficient network control and optimization of communication betweenthe base station 10 and the user equipment 20 can be achieved.

A condition is clarified with which the user equipment 20 can determine,based on information measured by the user equipment 20 before an SCellis deactivated, a receiving beam to be applied when the SCell isreactivated. If the condition is satisfied, the user equipment 20 mayapply a receiving beam to the reactivated SCell while assuming a TCIstate or QCL that is the same as the TCI state or the QCL employedbefore deactivation of the SCell.

For example, if the user equipment 20 has measured L1-RSRP and reporteda measurement result to the base station 10 prior to deactivation of theSCell, if a time interval from a timing of the measurement and reportingto a timing at which the SCell is reactivated is within y seconds, theuser equipment 20 may apply, to the reactivated SCell, the receivingbeam used at the timing of the measurement and reporting. In this case,the user equipment 20 does not need to perform L1-RSRP reporting and UERx beam sweeping. Alternatively, user equipment 20 may complete L1-RSRPreporting and UE Rx beam sweeping with a number of times of measurements(and/or reports) that is less than usual.

In addition to L1-RSRP, one or more of the following may be applied tothe measurement/report made by the user equipment 20 prior todeactivation of the SCell:

-   L3 measurement;-   Rx beam measurement (measured by CSI-RS for which “repetition” is    configured);-   Radio Link Monitoring;-   Beam Failure Detection, and Candidate Beam Detection.

The above-described “y seconds” may be switched depending on which ofthe above-described measurements is applied. Furthermore, “y seconds”may correspond to a TA timer.

Furthermore, for a measurement from among the above-describedmeasurements, if the time interval from the last report prior todeactivation of the SCell until activation of the SCell is within yseconds, the base station 10 may configure a TCI state at the time ofthe last report prior to the deactivation of the SCell for the userequipment 20. In this case, if the base station 10 does not provide aconfiguration, the user equipment 20 may autonomously assume QCL (i.e.,may assume that a transmit beam and a receiving beam that are the sameas those prior to the deactivation of the SCell are applicable forcommunication with the activated SCell).

Note that, as a specific example of a case in which, for measurementamong the above-described measurements, the time interval from the lastreport prior to the deactivation of the SCell until re-activation of theSCell exceeds y seconds, a case can be considered in which, for example,when the y seconds correspond to the TA timer, a timing at which theSCell is activated again is after expiration of the TA timer. In thiscase, the user equipment 20 may perform a random access procedure, andthe user equipment 20 may perform CSI reporting while assuming that theSSB monitored during the random access procedure is QCL with PDCCH andPDSCH.

The user equipment 20 may determine a receiving beam based onmeasurements made to the deactivated SCell, and after the SCell isactivated again, the user equipment 20 may assume that the referencesignals (RS) used for the measurement is QCL with the PDSCH and thePDCCH (i.e., may assume that the reference signal used for themeasurement, a signal of PDSCH, and a signal of PDCCH are transmittedwith the same beam), regardless of the TCI state. The user equipment 20may perform CSI reporting after the SCell is activated based on theabove-described assumption.

Specifically, the user equipment 20 may take over the reference signaland receiving beam used at the time of the last measurement, amongmeasurements made by the user equipment 20 to the deactivated SCell,made by the user apparatus 20 prior to the activation of the SCell,regardless of whether the measurement is reported to the base station10. In this case, the user equipment 20 may apply the reference signaland receiving beam, which are taken over, to the CSI reporting after theactivation of the SCell.

As a measurement made by the user equipment on the activated SCell, forexample, there is a L3 measurement.

For example, for a deactivated SCell, if the user equipment 20 performsL3 measurement, the user equipment 20 may take over the reference signaland received beam used during the last L3 measurement performed by theuser equipment 20 prior to the re-activation of SCell, even if a resultof the L3 measurement is not reported to the base station 10. In thiscase, the user equipment 20 may apply the reference signal and receivedbeam, which are taken over, to the CSI reporting after the SCell isactivated again.

Alternatively, the user equipment 20 may determine a receiving beambased on the measurement made to another serving cell, instead of themeasurement made to the deactivated SCell.

For example, if, in addition to the deactivated SCell, there are aPrimary Cell (PCell), a Primary Secondary Cell (PSCell), or an activatedSCell in a frequency band that is the same as the frequency band of thedeactivated SCell, the user equipment 20 may assume QCL based on aresult of measurement on the PCell and/or PSCell, even if there is nosignaling of a TCI state from the base station 10.

In this case, the measurements made to the other serving cells may be,for example, any of the following measurements:

-   L3 measurement;-   L1-RSRP reporting;-   Rx beam measurement (measured on a CSI-RS for which “repetition” is    configured);-   Radio Link Monitoring;-   Beam Failure Detection, and Candidate Beam Detection.

(Dual Connectivity (DC)/Carrier Aggregation (CA))

Long Term Evolution (LTE) and New Radio (NR) of the Third GenerationPartnership Project (3GPP) support Dual Connectivity (DC) and CarrierAggregation (CA) to increase capacity.

In DC or CA, multiple carriers (which may be referred to as cells) areused for communication. As types of cells, there are at least thefollowing three types:

-   Primary Cell (PCell): A cell that secures connectivity between the    user equipment 20 and the base station 10 and provides communication    of control signals. For DC, there is one in a Master Cell Group    (MCG).-   Primary Secondary Cell (PSCell): One PSCell is configured within a    Secondary Cell Group (SCG) for DC. A cell secures connectivity at    the SCG side, and provides communication of control signals.-   Secondary Cell (SCell): A cell that is added to a PCell or a PSCell    for CA.

For SCell, for example, a two-step configuration has been adopted inwhich it is added to PCell by Radio Resource Control (RRC) and thenactivated/deactivated by Medium Access Control (MAC) Control Element(CE).

DC between LTE and NR is called E-UTRA-NR (EN) DC when PCell is a cellof LTE and NR-E-UTRA (NE) DC when PCell is a cell of NR. CAs usingcomponent carriers of respective different Radio Access Technologies(RATs) (e.g., LTE component carriers and NR component carriers) are notsupported. DC is a technology that can be applied to backhaul, which isrelatively inexpensive and that allows a delay.

FIG. 5 is a diagram illustrating an example of a cell configuration ofDC in which only a PCell is included in an MCG and a PSCell and threeSCells are included in a SCG. In the example illustrated in FIG. 5, inthe SCG, CA is configured between PCell and each SCell of the threeSCells.

FIG. 6 is a diagram illustrating an example of a cell configuration ofDC in which a PCell and SCell are included in an MCG and a PSCell andtwo SCells are included in a SCG. In the example illustrated in FIG. 6,in the MCG, CA is configured between PCell and the SCell, and, in theSCG, CA is configured between the PSCell and each SCell of the twoSCells.

(Known Cell)

Upon receipt of an indication to activate an SCell, the user equipment20 is required to perform preprocessing for data transmission andreception. Such preprocessing includes at least a process of decoding areceived MAC command by the user equipment 20, detection of PSS/SSS ofthe target SCell, a time and frequency synchronization process, and aprocess for a CSI report.

However, depending on operational and radio-wave propagation conditions,the user equipment 20 may be allowed to omit performing some of thepreprocessing required for connection to the SCell.

For example, the measurement of L3-RSRP may have been completedimmediately prior to receiving an instruction to activate the SCell, andif that prior information is present, PSS/SSS detection of the targetSCell may be omitted.

If the user equipment 20 holds such prior information for the SCell, thecorresponding SCell is referred to as a known cell. For FR1, if theSCell is a known cell, it is assumed that a part of the SCell activationdelay can be shortened. In the base station 10, after transmitting anSCell activation command, early scheduling can be made.

Currently, a definition of a known cell in FR2 has been studied in RAN4RRM of the 3GPP. As for the prior information of an SCell held by theuser equipment 20, if a time period during which the cell can bedetermined to be a known cell is set to be too long, accuracy of theinformation learned by the user equipment 20 may be reduced and thefailure rate of the SCell activation may increase. As for the priorinformation of an SCell held by the user equipment 20, if a time periodduring which the cell can be determined to be a known cell is set tooshort, redundant measurement may be performed and a time required forSCell activation may increase.

(Power Class)

In NR, a plurality of Power Classes (PCs) is specified for the userequipment 20 while assuming various use cases and related constraints(e.g., size, a number of antennas).

PC1: Fixed wireless access (FWA) UE

PC2: Vehicular UE

PC3: Handheld UE

PC4: High power non-handheld UE

A different requirement on radio (RF) or the like is defined per PC.From among a plurality of PCs, it is assumed for the PC1 that mobilityof the user equipment 20 is extremely low and that a coherence timerepresenting a time during which a condition of a propagation path isconstant is longer than a coherence time of another PC.

Here it is assumed that components of SCell activation delay depend on aPC of the user equipment 20. For example, even in a case of a knowncell, a case is assumed where L1-RSRP measurement/report is necessary.For example, for PC1, a condition of a propagation path is not expectedto change significantly, so that SCell activation delay need not includeL1-RSRP reporting time. However, for PC2, 3, and 4, SCell activationdelay may include L1-RSRP reporting time.

(Known Cell Condition)

For FR1, conditions are specified under which an SCell can be regardedas a known cell (Non-Patent Document 3).

An SCell on FR1 is known if the following conditions are satisfied:

-   For FR1, for a time period equal to max ([5] measCycleScell, [5] DRX    cycles) prior to receipt of an SCell activation command, a UE has    sent a valid measure report for the SCell to be activated, and the    measured SSB remains detectable according to a cell identification    condition.-   An SSB measured in a time period equal to max([5] measCycleScell,    [5] DRX cycles) prior to receipt of an SCell activation command    remains detectable during the SCell activation delay, according to    the cell identification conditions.

In a case other than the above-described case, an SCell on FR1 isunknown.

The above-described conditions under which an SCell can be regarded as aknown cell are specified for FR1. For FR2, per Power Class of the userequipment 20, a condition may be defined under which an SCell can beregarded as a known cell. Namely, conditions under which an SCelldefined for one Power Class can be regarded as a known cell may differfrom conditions under which the SCell defined for another Power Classcan be regarded as a known cell.

For example, in FR2, conditions under which an SCell for the userequipment 20 of PC1 can be regarded as a known cell may differ fromconditions under which the SCell for the user equipment 20 of another PCcan be regarded as a known cell. For example, in FR2, conditions underwhich an SCell for the user equipment 20 of PC1 can be regarded as aknown cell may be extended from conditions under which the SCell for theuser equipment 20 of another PC may be regarded as a known cell. Forexample, in FR2, conditions under which an SCell for the user equipment20 of PC2, PC3, and PC4 can be regarded as a known cell may be the same.

Here, the user equipment 20 of PC1 is FWA UE and the mobility of theuser equipment 20 is assumed to be extremely low. Accordingly,conditions under which an SCell for the user equipment 20 of PC1 can beregarded as a known cell can be extended in comparison to conditionsunder which the SCell for the user equipment 20 of another PC can beregarded as a known cell.

For example, in FR2, conditions under which an SCell can be regarded asa known cell may be defined based on the parameters X, Y, and Z, asdescribed below. Specifically, X, Y, and Z are parameters relating to acoherence time with respect to a variation of a condition of apropagation path, and some or all of the parameters may be the samevalue. Furthermore, X, Y, and Z need not be expressed in ms, and may beexpressed as a number of samples, such as a number of symbols or anumber of slots, or may be expressed using other expressions, such as anumber of measurement samples.

-   For a period equal to X ms prior to receipt of an SCell activation    command, the user equipment 20 has sent a valid L3-RSRP measurement    report along with a beam index of the cell, and according to a cell    identification condition, the cell remains detectable.-   An SSB measured for a period equal to Y ms prior to receipt of an    SCell activation command remains detectable during SCell activation    delay, according to the cell identification condition.-   The user equipment 20 chooses an active TCI state based on    transmission of a valid L3-RSRP measurement report for a period    equal to Z ms, after transmitting a valid L3-RSRP measurement report    with a beam index of the cell.

Additionally or alternatively, in FR2, the above-described values of X,Y, and Z may be the same values as a period of L3 measurement.Alternatively, in FR2, the above-described values of X, Y, and Z may bea multiple of the period of the L3 measurement.

For example, in FR2, the values of X, Y, and Z for PC1 may be 40samples, respectively. Additionally, for example, in FR2, the values ofX, Y, and Z for PC2, PC3, and PC4 may be 24 samples, respectively.

Alternatively, in FR2, the values of X, Y, and Z for PC1 may be a valueobtained by multiplying 40 samples by a specific scaling factor,respectively. Additionally, for example, in FR2, the values of X, Y, andZ for PC2, PC3, and PC4 may be a value obtained by multiplying 24samples by the above-described specific scaling factor, respectively.For example, in FR2, the values of X, Y, and Z for PC1 may be 5 samples,respectively, and in FR2, the values of X, Y, and Z for PC2, PC3, andPC4 may be 3 samples, respectively. That is, the specific scaling factordescribed above may be, for example, 1/8.

For example, in FR2, conditions under which an SCell may be regarded asa known cell may be determined based on max(K1 measCycleSCell, K2 DRXcycles). Here, the values of K1 and K2 may be the same or different. Forexample, the value of K1 and/or the value of K2 may be specified perPower Class. Namely, the value of K1 and/or the value of K2 configuredfor one PC may be different from the value of K1 and/or the value of K2configured for another PC.

For example, the value of K1 and the value of K2 for PC1 in FR2 may bethe same as the value of K1 and the value of K2 in FR1. For example, thevalue of K1 for PC1 in FR2 may be 5 and the value of K2 may be 5.Furthermore, for example, the value of K1 for PC2, PC3 and PC4 in FR2may be less than the value of K1 for PC1 in FR2, and the value of K2 forPC2, PC3 and PC4 in FR2 may be less than the value of K2 for PC1 in FR2.For example, the value of K1 for PC2 in FR2 may be 3 and the value of K2may be 3.

For example, the value of K1 for PC2, PC3 and PC4 in FR2 may be the sameas the value of K1 in FR1, and the value of K2 for PC2, PC3 and PC4 inFR2 may be the same as the value of K2 in FR1. For example, the value ofK1 for PC2, PC3 and PC4 in FR2 may be 5, and the value of K2 for PC2,PC3 and PC4 in FR2 may be 5. Additionally, for example, the value of K1for PC1 in FR2 may be greater than the value of K1 for PC2, PC3 and PC4in FR2, and the value of K2 for PC1 in FR2 may be greater than the valueof K2 for PC2, PC3 and PC4 in FR2. For example, the value of K1 for PC1in FR2 may be 8, and the value of K2 for PC1 in FR2 may be 8. Forexample, the value of K1 for PC1 in FR2 may be 5 or 3 and the value ofK2 may be 5 or 3. For example, the value of K1 for PC2, PC3 and PC4 inFR2 may be less than the value of K1 for PC1 in FR2, and the value of K2for PC2, PC3 and PC4 in FR2 may be less than the value of K2 for PC1 inFR2. For example, the value of K1 for PC2 in FR2 may be 3 or 1 and thevalue of K2 may be 3 or 1.

As described above, conditions under which an SCell may be regarded as aknown cell or an unknown cell may be specified in a technicalspecification document. However, in some cases, a network side may beable to configure the user equipment 20 by signaling, so that an SCellcan be regarded as a known cell or an unknown cell under specificconditions.

For example, if a process of activating a specific SCell is unstable anda network side can allow a delay in activating the SCell to some extent,even if the SCell satisfies a condition specified in a technicalspecification document under which the SCell can be regarded as a knowncell, it can be considered that necessity for regarding the SCell to bea known cell is low. In such a case, the network side may return theSCell to an unknown cell, even if the SCell satisfies a condition of aknown cell specified in a technical specification document (the SCellmay be fallback to an unknown cell).

Furthermore, even if a specific SCell satisfies conditions specified ina technical specification document under which the SCell can be regardedas an unknown cell, the network may also be able to configure, bysignaling, the user equipment 20 to regard the SCell as a known cellunder specific conditions. For example, if it is desired to reduce SCellactivation delay, the network may provide signaling to force the userequipment 20 to regard the SCell as a known cell.

For example, by explicit or implicit signaling from the base station(gNB) 10, the user equipment 20 may be configured to activate a specificSCell, while regarding the specific SCell as a known cell.

Additionally, for example, by explicit or implicit signaling from thebase station (gNB) 10, the user equipment 20 may be configured toactivate a specific SCell, while regarding the specific SCell as anunknown cell.

For example, when there is a large variation in the condition of apropagation path between the user equipment 20 and a specific SCell, thebase station 10 may configure the user equipment 20 to activate thespecific SCell while regarding the SCell as an unknown cell. Forexample, the base station 10 may configure the user equipment 20 toregard a specific SCell as an unknown cell if a value of ReferenceSignal Received Power (RSRP) for the specific SCell falls below apredetermined threshold value. Additionally or alternatively, forexample, the base station 10 may configure the user equipment 20 toregard a specific SCell as an unknown cell if variance of RSRP in aconstant sample for the specific SCell exceeds a predetermined thresholdvalue.

(A State Other than Known/Unknown)

In the above-described embodiments, as a state of an SCell, two statesare specified, which are a known cell and an unknown cell. However, astate of an SCell is not limited to the above-described embodiments. Forexample, as states of an SCell, three states may be specified, which area known cell, an unknown cell, and a semi-known cell.

For example, for a specific SCell, if L3 measurement is reported fromthe user equipment 20 without an SSB index and only timingsynchronization is established between the specific SCell and the userequipment 20, the SCell may be regarded as a semi-known cell. In thiscase, the user equipment 20 does not know only an appropriate receivingbeam. Accordingly, the user equipment 20 may only perform L1-RSRPmeasurement/reporting, and the user equipment 20 need not perform L3measurement/reporting. For example, if an L3 measure is reported with anSSB index, the user equipment 20 need not perform an L1-RSRPmeasure/report.

If a specific SCell is a semi-known cell, SCell activation delay neednot include the time required to detect PSS/SSS of the target SCell.

In the above-described embodiments, it is assumed that, in FR2, threestates are specified as states of an SCell, which are a known cell, anunknown cell, and a semi-known cell. However, embodiments of the presentinvention are not limited to the above-described embodiments. Forexample, in FR1, three states of an SCell may be defined, which are aknown cell, an unknown cell, and a semi-known cell.

Currently, in RAN1 of the 3GPP release 16, a state has been studied inwhich an SCell is activated and a number of Bandwidth Parts (BWPs) iszero (i.e., energy consumption can be saved without SCell deactivation).Specifically, it has been studied as to whether to perform CSImeasurement/reporting, Beam Failure Detection (BFD), and Radio LinkMonitoring (RLM) (which are usually performed only in an active BWP), ina state of an SCell in which the SCell is activated and the number ofBWPs is 0.

The above-described conditions under which an SCell can be regarded as aknown cell, the conditions under which an SCell can be regarded as anunknown cell, the conditions under which an SCell can be regarded as asemi-known cell, and the like may be applied to a state of an SCell inwhich the SCell is activated and in which a number of BWPs is zero.

In the above-described embodiments, channels and signaling methods ofNEW Radio (NR) are assumed. However, embodiments of the presentinvention are not limited to NR, and may be applied to channels andsignaling methods that have similar functions as those of NR. Forexample, the embodiments of the present invention may be applied toLTE/LTE-A.

In the above-described embodiments, various examples of signaling aredescribed. However, the signaling is not limited to explicit method.Signaling may be made implicitly, or signaling may be uniquely specifiedin a technical specification document.

In the above-described embodiments, various examples of signaling aredescribed. However, examples of signaling are not limited to theexamples described in the embodiments, and signaling of a differentlayer may be used, such as Radio Resource Control (RRC) layer signaling,a MAC CE, and Downlink Control Information (DCI), or Master InformationBlock (MIB), System Information Block (SIB), and the like may be used.For example, RRC signaling may be combined with DCI. RRC signaling maybe combined with MAC CE. RRC signaling may also be combined with DCI andMAC CE.

The above-described embodiments and modifications can be combined witheach other, and the features described in these examples can be combinedwith each other in various combinations. The present invention is notlimited to the specific combinations disclosed the specification. In theembodiments, the feature assumed to be applied to FR1 may be applied toFR2, and the feature assumed to be applied to FR2 may be applied to FR1.

(Device Configuration)

Next, an example of the functional configuration of the base station 10and the user equipment 20 for performing the processes and operationsdescribed above is described. The base station 10 and the user equipment20 include functions for implementing the above-described embodiments.However, each of the base station 10 and the user equipment 20 mayinclude only a part of the functions in the embodiments.

<Base Station Apparatus 10>

FIG. 7 is a diagram illustrating an example of the functionalconfiguration of the base station 10. As illustrated in FIG. 7, the basestation 10 includes a transmitting unit 110, a receiving unit 120, and acontrol unit 130. The functional configuration illustrated in FIG. 7 ismerely one example. The functional division and names of functionalunits may be any division and names, provided that the operationaccording to the embodiments of the present invention can be performed.

The transmitting unit 110 includes a function for generating a transmitsignal from transmit data, and the transmitting unit 110 transmits thetransmit signal through radio. The receiving unit 120 receives varioustypes of signals through radio, and the receiving unit 120 obtains ahigher layer signal from the received physical layer signal.Furthermore, the receiving unit 120 includes a measurement unit thatperforms measurement of a received signal to obtain received power, andso forth.

The control unit 130 controls the base station 10. Note that a functionof the control unit 130 related to transmission may be included in thetransmitting unit 110 and a function of the control unit 130 related toreception may be included in the receiving unit 120.

In the base station 10, the control unit 130 calculates an optimum beambased on the quality of each beam reported from the user equipment 20,and the control unit 130 generates, as a TCI state, informationindicating that data and/or control signals are transmitted with thecalculated beam. The transmitting unit 110 transmits a signal includinga TCI state to the user equipment 20.

In the base station 10, the transmitting unit 110 periodically transmitsa plurality of reference signals (beams) such as a Beam ManagementReference signal (BM-RS), and/or a Radio Link Monitoring Referencesignal (RLM-RS), in addition to one beam for transmitting a signal ofPDCCH and a signal of PDSCH.

The control unit 130 of the base station 10 generates indicationinformation for causing the user equipment 20 to activate an SCell, andthe transmitting unit 110 transmits the indication information to theuser equipment 20. For example, the receiving unit 120 of the basestation 10 may receive a signal including UE Capability from the userequipment 20, and the control unit 130 may identify a power class of theuser equipment 20 based on the UE Capability and specify conditionsunder which the user equipment 20 may regard the SCell as a known cell.

For example, when a process of activating a specific SCell is unstable,and if the specific SCell satisfies a condition specified in a technicalspecification document under which the SCell can be regarded as a knowncell, the control unit 130 of the base station 10 may generateconfiguration information that is for causing the user equipment 20 toregard the specific SCell as an unknown cell and that is for causing theuser equipment 20 to activate the specific SCell, and the transmittingunit 110 may transmit a signal including the configuration informationto the user equipment 20. For example, when an RSRP value for aparticular SCell falls below a predetermined threshold value, thecontrol unit 130 of the base station 10 may generate configurationinformation that is for causing the user equipment 20 to regard thespecific SCell as an unknown cell and that is for causing the userequipment 20 to activate the specific SCell, and the transmitting unit110 may transmit a signal including the configuration information to theuser equipment 20. Additionally or alternatively, for example, ifvariance of RSRP in a constant sample for a specific SCell exceeds apredetermined threshold value, the control unit 130 of the base station10 may generate configuration information that is for causing the userequipment 20 to regard the specific SCell as an unknown cell and that isfor causing the user equipment 20 to activate the particular SCell, andthe transmitting unit 110 may transmit a signal including theconfiguration information to the user equipment 20.

Even if a specific SCell satisfies conditions of an unknown cell asspecified in a technical specification document, for example, if it isdesired to reduce delay in activation of the SCell, the control unit 130of the base station 10 may generate configuration information that isfor causing the user equipment 20 to regard the specific SCell as aknown cell and that is for causing the user equipment 20 to performactivation of the specific SCell, and the transmitting unit 110 maytransmit a signal including the configuration information to the userequipment 20.

<User Equipment 20>

FIG. 8 is a diagram illustrating an example of the functionalconfiguration of the user equipment 20. As illustrated in FIG. 8, theuser equipment 20 includes a transmitting unit 210, a receiving unit220, and a control unit 230. The functional configuration illustrated inFIG. 8 is merely an example. The functional division and names offunctional units may be any division and names, provided that theoperation according to the embodiments can be performed.

The transmitting unit 210 includes a function for generating a signal tobe transmitted to the base station 10 and transmitting the signalthrough radio. The receiving unit 220 includes a function for receivingvarious types of signals transmitted from the base station 10 andobtaining, for example, higher layer information from the receivedsignals. The receiving unit 220 includes a measurement unit thatmeasures a received signal to obtain a received power.

The control unit 230 controls the user equipment 20. The function of thecontrol unit 230 related to transmission may be included in thetransmitting unit 210, and the function of the control unit 230 relatedto reception may be included in the receiving unit 220.

In the user equipment 20, the receiving unit 220 measures quality of abeam (RSRP: Reference Signal Received Power) using a reference signaltransmitted by a resource signaled by the base station 10, and thetransmitting unit 210 transmits the measured quality to the base station10.

For example, after an SCell is deactivated, if the receiving unit 220 ofthe user equipment 20 receives an activation command for the SCell, thecontrol unit 230 of the user equipment 20 sets a condition under whichthe SCell can be regarded as a known cell, based on a power class of theuser equipment 20. Prior to deactivation of an SCell, for example, ifL1-RSRP is measured and a measurement result is reported to the basestation 10 during a time period in which the SCell can be regarded as aknown cell, the control unit of the user equipment 20 may apply areceiving beam at the time of the measurement and reporting to theactivated SCell.

For example, in FR2, the control unit 230 of the user equipment 20 mayregard an SCell as a known cell if the transmitting unit 210 of the userequipment 20 has transmitted a valid L3-RSRP measurement report with abeam index of the cell during a time period equal to X ms, prior toreceipt of an SCell activation command, if the SCell is determined to bedetectable by a cell identification condition, if an SSB measured in atime period equal to Y ms, prior to receipt of the SCell activationcommand, is determined to be detectable during SCell activation delayaccording to the cell identification condition, and if the transmittingunit 210 of the user equipment 20 selects an active TCI state based ontransmission of the valid L3-RSRP measurement report during a timeperiod equal to Z ms, after transmitting the valid L3-RSRP measurementreport with the beam index of the cell. In a case other than theabove-described case, the control unit 230 of the user equipment 20 mayregard the SCell as an unknown cell.

For example, in FR2, the control unit 230 of the user equipment 20 mayregard an SCell as a known cell if the transmitting unit 210 of the userequipment 20 has transmitted a valid measurement report for the SCell tobe activated during a time period equal to max (K1 measCycleSCell, K2DRX cycles), prior to receipt of an SCell activation command, if ameasured SSB is determined to be detectable by a cell identificationcondition, and if the SSB measured during a time period equal to max (K1measCycleSCell, K2 DRX cycles), prior to receipt of an SCell activationcommand, is determined to be detectable during SCell activation delayaccording to the cell identification condition. In this case, thecontrol unit 230 of the user equipment 20 may determine a value of K1and/or a value of K2 based on a power class of the user equipment 20.

For example, if the receiving unit 220 of the user equipment 20 receivesa signal transmitted from the base station 10, and if the receivedsignal includes configuration information that is for regarding aspecific SCell as a known cell and that is for causing the userequipment 20 to activate the specific SCell, the control unit 230 of theuser equipment 20 may activate the specific SCell while regarding thespecific SCell as an unknown cell.

If, for example, the receiving unit 220 of the user equipment 20receives a signal transmitted from the base station 10, and the receivedsignal includes configuration information that is for regarding aspecific SCell as a known cell and that is for causing the userequipment 20 to activate the specific SCell, the control unit 230 of theuser equipment 20 may activate the specific SCell while regarding thespecific SCell as a known cell.

<Hardware Configuration>

The block diagrams (FIG. 7 to FIG. 8) used for the description of theabove embodiments show blocks of functional units. These functionalblocks (components) are implemented by any combination of at least oneof hardware and software. In addition, the implementation method of eachfunctional block is not particularly limited. That is, each functionalblock may be implemented using a single device that is physically orlogically combined, or may be implemented by directly or indirectlyconnecting two or more devices that are physically or logicallyseparated (e.g., using wire or radio) and using these multiple devices.The functional block may be implemented by combining software with theabove-described one device or the above-described plurality of devices.Functions include, but are not limited to, judgment, decision,determination, computation, calculation, processing, derivation,research, search, verification, reception, transmission, output, access,resolution, choice, selection, establishment, comparison, assumption,expectation, deeming, broadcasting, notifying, communicating,forwarding, configuring, reconfiguring, allocating, mapping, assigning,and so forth. For example, a functional block (component) that functionsto transmit is called a transmitting unit or a transmitter. In eithercase, as described above, the implementation method is not particularlylimited.

For example, the base station 10 and the user equipment 20 according toan embodiment of the present invention may function as computersperforming the process of the radio communication according to theembodiment of the present invention. FIG. 7 is a diagram illustrating anexample of a hardware configuration of the base station 10 and the userequipment 20 according to the embodiment. Each of the above-describedbase station 10 and user equipment 20 may be physically configured as acomputer device including a processor 1001, a storage device 1002, anauxiliary storage device 1003, a communication device 1004, an inputdevice 1005, an output device 1006, a bus 1007, and so forth.

Note that, in the following description, the term “device” can bereplaced with a circuit, a device, a unit, and so forth. The hardwareconfiguration of the base station 10 and the user equipment 20 may beconfigured to include one or more of the devices depicted in the figure,which are indicated by 1001 through 1006, or may be configured withoutsome devices.

Each function of the base station 10 and the user equipment 20 isimplemented by loading predetermined software (program) on hardware,such as the processor 1001 and the storage device 1002, so that theprocessor 1001 performs computation and controls communication by thecommunication device 1004, and at least one of reading and writing ofdata in the storage device 1002 and the auxiliary storage device 1003.

The processor 1001, for example, operates an operating system to controlthe entire computer. The processor 1001 may be configured with a centralprocessing unit (CPU: Central Processing Unit) including an interfacewith a peripheral device, a control device, a processing device, aregister, and so forth.

Additionally, the processor 1001 reads a program (program code), asoftware module, data, or the like from at least one of the auxiliarystorage device 1003 and the communication device 1004 to the storagedevice 1002, and executes various processes according to these. As theprogram, a program is used which causes a computer to execute at least apart of the operations described in the above-described embodiment. Forexample, the control unit 130 of the base station 10 may be implementedby a control program that is stored in the storage device 1002 and thatis operated by the processor 1001. While the various processes describedabove are described as being executed in one processor 1001, they may beexecuted simultaneously or sequentially by two or more processors 1001.The processor 1001 may be implemented by one or more chips. The programmay be transmitted from a network via a telecommunications line.

The storage device 1002 is a computer readable storage medium, and, forexample, the storage device 1002 may be formed of at least one of a ReadOnly Memory (ROM), an Erasable Programmable ROM (EPROM), an ElectricallyErasable Programmable ROM (EEPROM), a Random Access Memory (RAM), andthe like. The storage device 1002 may be referred to as a register, acache, a main memory (main storage device), or the like. The storagedevice 1002 may store a program (program code), a software module, andso forth, which can be executed for implementing the radio communicationmethod according to the embodiments of the present disclosure.

The auxiliary storage device 1003 is a computer readable storage mediumand may be formed of, for example, at least one of an optical disk, suchas a Compact Disc ROM (CD-ROM), a hard disk drive, a flexible disk, anoptical magnetic disk (e.g., a compact disk, a digital versatile disk, aBlu-ray (registered trademark) disk), a smart card, a flash memory(e.g., a card, a stick, a key drive), a floppy (registered trademark)disk, a magnetic strip, and so forth. The auxiliary storage device 1003may be referred to as an auxiliary storage device. The above-describedstorage medium may be, for example, a database including at least one ofthe storage device 1002 and the auxiliary storage device 1003, a server,or any other suitable medium.

The communication device 1004 is hardware (transmitting and receivingdevice) for performing communication between computers through at leastone of a wired network and a wireless network, and is also referred to,for example, as a network device, a network controller, a network card,a communication module, or the like. The communication device 1004 maybe configured to include, for example, a high frequency switch, aduplexer, a filter, a frequency synthesizer, and the like, to implementat least one of frequency division duplex (FDD: Frequency DivisionDuplex) and time division duplex (TDD: Time Division Duplex).

The input device 1005 is an input device (e.g., a keyboard, mouse,microphone, switch, button, or sensor) that receives an external input.The output device 1006 is an output device (e.g., a display, speaker, orLED lamp) that implements an external output. The input device 1005 andthe output device 1006 may have an integrated configuration (forexample, a touch panel).

Each device, such as the processor 1001 and the storage device 1002, isalso connected by the bus 1007 for communicating information. The bus1007 may be formed of a single bus or may be formed of different busesbetween devices.

The base station 10 and the user equipment 20 may each include hardware,such as a microprocessor, a digital signal processor (DSP: DigitalSignal Processor), an Application Specific Integrated Circuit (ASIC), aProgrammable Logic Device (PLD), and a Field Programmable Gate Array(FPGA), which may implement some or all of the functional blocks. Forexample, processor 1001 may be implemented using at least one of thesehardware components.

(Conclusion of the Embodiments)

In this specification, at least the user equipment and the communicationmethod described below are disclosed.

A user equipment including a transmitting unit that transmits ameasurement result of a secondary cell; a receiving unit that receives asignal to activate the secondary cell; and a control unit that usespreviously obtained information of the secondary cell to activate thesecondary cell when a predetermined condition associated with a powerclass of the user equipment is satisfied.

According to the above-described configuration, a condition forspecifying whether information on a secondary cell previously obtainedby the user equipment is used for activation of the secondary cell canbe specified per power class of the user equipment. Accordingly, forPower Class 1, i.e., for a Fixed wireless access (FWA) UE, a conditioncan be applied which is extended compared to a condition applied toanother power class.

The predetermined condition may include a condition that thetransmitting unit has transmitted a valid measurement result of thesecondary cell within a predetermined time period before receiving thesignal to activate the secondary cell.

The predetermined time period may be set according to the power class ofthe user equipment.

When the power class of the user equipment is a power class of a radiodevice that is intended for fixed use, the predetermined time period maybe set to be longer than a predetermined time period specified foranother power class.

A communication method by user equipment, the method includingtransmitting a measurement result of a secondary cell; receiving asignal to activate the secondary cell; and using previously obtainedinformation of the secondary cell to activate the secondary cell when apredetermined condition associated with a power class of the userequipment is satisfied.

(Supplemental Embodiments)

While the embodiments of the present invention are described above, thedisclosed invention is not limited to the described embodiments, andthose skilled in the art will appreciate various alterations,modifications, alternatives, and substitutions. Descriptions areprovided using specific numerical examples to facilitate understandingof the invention, but, unless as otherwise specified, these values aremerely examples and any suitable value may be used. Classification ofthe items in the above descriptions is not essential to the presentinvention, and the items described in two or more items may be used incombination as needed, or the items described in one item may be applied(unless inconsistent) to the items described in another item. Theboundaries of functional units or processing units in the functionalblock diagram do not necessarily correspond to the boundaries ofphysical components. An operation by a plurality of functional units maybe physically performed by one component or an operation by onefunctional unit may be physically executed by a plurality of components.For the processing procedures described in the embodiment, the order ofprocessing may be changed as long as there is no contradiction. For theconvenience of the description of the process, the base station 10 andthe user equipment 20 are described using functional block diagrams, butsuch devices may be implemented in hardware, software, or a combinationthereof. Software operated by a processor included in the base station10 in accordance with embodiments of the present invention and softwareoperated by a processor included in the user equipment 20 in accordancewith embodiments of the present invention may be stored in a randomaccess memory (RAM), a flash memory (RAM), a read-only memory (ROM), anEPROM, an EEPROM, a register, a hard disk (HDD), a removable disk, aCD-ROM, a database, a server, or any other suitable storage medium,respectively.

Notification of information is not limited to the aspects/embodimentsdescribed in the disclosure, and notification of information may be madeby another method. For example, notification of information may beimplemented by physical layer signaling (e.g., DCI (Downlink ControlInformation), UCI (Uplink Control Information), higher layer signaling(e.g., RRC (Radio Resource Control) signaling, MAC (Medium AccessControl) signaling, broadcast information (MIB (Master InformationBlock), SIB (System Information Block))), or other signals orcombinations thereof. RRC signaling may be referred to as an RRCmessage, for example, which may be an RRC connection setup message, anRRC connection reconfiguration message, or the like.

The aspects/embodiments described in this disclosure may be applied to asystem using at least one of Long Term Evolution (LTE), LTE-Advanced(LTE-A), SUPER 3G, IMT-Advanced, 4th generation mobile communicationsystem (4G), 5th generation mobile communication system (5G), FutureRadio Access (FRA), W-CDMA (Registered Trademark), GSM (RegisteredTrademark), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi(Registered Trademark)), IEEE 802.16 (WiMAX (Registered Trademark)),IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (Registered Trademark), anyother appropriate system, and a next generation system extended based ontheses. Additionally, a plurality of systems may be combined (e.g., acombination of at least one of LTE and LTE-A and 5G) to be applied.

The processing procedures, sequences, flow charts, or the like of eachaspect/embodiment described in this disclosure may be reordered,provided that there is no contradiction. For example, the methodsdescribed in this disclosure present elements of various steps in anexemplary sequence and are not limited to the particular sequencepresented.

The particular operation described in this disclosure to be performed bythe base station 10 may be performed by an upper node in some cases. Itis understood that in a network formed of one or more network nodeshaving the base station 10, various operations performed forcommunicating with the terminal may be performed by at least one of thebase station 10 and a network node other than the base station 10 (e.g.,MME or S-GW can be considered, however, the network node is not limitedto these). The case is exemplified above in which there is one networknode other than the base station 10. However, the network node otherthan the base station 10 may be a combination of multiple other networknodes (e.g., MME and S-GW).

Input and output information may be stored in a specific location (e.g.,memory) or managed using management tables. Input and output informationmay be overwritten, updated, or added. Output information may bedeleted. The input information may be transmitted to another device.

The determination may be made by a value (0 or 1) represented by 1 bit,by a true or false value (Boolean: true or false), or by comparison ofnumerical values (e.g., a comparison with a predefined value).

The aspects/embodiments described in this disclosure may be used alone,in combination, or switched with implementation. Notification ofpredetermined information (e.g. “X” notice) is not limited to a methodthat is explicitly performed, and may also be made implicitly (e.g. “nonotice of the predetermined information”).

Software should be broadly interpreted to mean, regardless of whetherreferred to as software, firmware, middleware, microcode, hardwaredescription language, or any other name, instructions, sets ofinstructions, code, code segments, program code, programs, subprograms,software modules, applications, software applications, softwarepackages, routines, subroutines, objects, executable files, executablethreads, procedures, functions, and so forth.

Software, instructions, information, or the like may also be transmittedand received via a transmission medium. For example, when software istransmitted from a website, server, or other remote source using atleast one of wireline technology (such as coaxial cable, fiber opticcable, twisted pair, digital subscriber line) and wireless technology(e.g., infrared or microwave), at least one of these wireline technologyand wireless technology is included within the definition of atransmission medium.

The information, signals, or the like described in this disclosure maybe represented using any of a variety of different techniques. Forexample, data, instructions, commands, information, signals, bits,symbols, chips, or the like, which may be referred to throughout theabove description, may be represented by voltages, currents,electromagnetic waves, magnetic fields or magnetic particles, opticalfields or photons, or any combination thereof.

The terms described in this disclosure and those necessary forunderstanding this disclosure may be replaced by terms having the sameor similar meanings. For example, at least one of the channels and thesymbols may be a signal (signaling). The signal may also be a message.The component carrier may also be referred to as a carrier frequency,cell, frequency carrier, and so forth.

As used in this disclosure, the terms “system” and “network” are usedinterchangeably. The information, parameters, or the like described inthe present disclosure may also be expressed using absolute values,relative values from predetermined values, or they may be expressedusing corresponding separate information. For example, radio resourcesmay be those indicated by an index.

The name used for the parameters described above are not restrictive inany respect. In addition, the mathematical equations using theseparameters may differ from those explicitly disclosed in thisdisclosure. Since the various channels (e.g., PUCCH and PDCCH) andinformation elements can be identified by any suitable name, the variousnames assigned to these various channels and information elements arenot in any way limiting.

In this disclosure, the terms “Base Station,” “Radio Base Station,”“Fixed Station,” “NodeB,” “eNodeB(eNB),” “gNodeB (gNB),” “Access Point,”“Transmission Point,” “Reception Point,” “Transmission/Reception Point,”“Cell,” “Sector,” “Cell Group,” “Carrier,” “Component Carrier,” and thelike may be used interchangeably. The base stations may be referred toas macro-cell, small-cell, femto-cell, pico-cell, or the like.

The base station can accommodate one or more (e.g., three) cells. Wherethe base station accommodates a plurality of cells, the entire coveragearea of the base station can be divided into a plurality of smallerareas, each smaller area can also provide communication services bymeans of a base station subsystem (e.g., an indoor small base station(RRH) or a remote Radio Head). The term “cell” or “sector” refers to aportion or all of the coverage area of at least one of the base stationand base station subsystem that provides communication services at thecoverage.

In this disclosure, terms such as “mobile station (MS: Mobile Station),”“user terminal,” “user equipment (UE: User Equipment),” and “terminal”may be used interchangeably.

The mobile station may be referred to by one of ordinary skill in theart as a subscriber station, a mobile unit, a subscriber unit, awireless unit, a remote unit, a mobile device, a wireless device, awireless communication device, a remote device, a mobile subscriberstation, an access terminal, a mobile terminal, a wireless terminal, aremote terminal, a handset, a user agent, a mobile client, a client, orsome other suitable term.

At least one of a base station and a mobile station may be referred toas a transmitter, receiver, communication device, or the like. At leastone of a base station and a mobile station may be a device installed ina mobile body, a mobile body itself, or the like. The mobile body may bea vehicle (e.g., a car or an airplane), an unmanned mobile (e.g., adrone or an automated vehicle), or a robot (manned or unmanned). Atleast one of a base station and a mobile station includes a device thatdoes not necessarily move during communication operations. For example,at least one of a base station and a mobile station may be an Internetof Things (IoT) device such as a sensor.

In addition, the base station in the present disclosure may be replacedwith the user terminal. For example, various aspects/embodiments of thepresent disclosure may be applied to a configuration in whichcommunication between the base stations and the user terminal isreplaced with communication between multiple user terminals (e.g., maybe referred to as Device-to-Device (D2D) or Vehicle-to-Everything(V2X)). In this case, a configuration may be such that theabove-described function of the user equipment 20 is included in theuser terminal 20. The terms “up” and “down” may also be replaced withthe terms corresponding to terminal-to-terminal communication (e.g.,“side”). For example, an uplink channel, a downlink channel, or the likemay be replaced with a sidelink channel. Similarly, the user terminalaccording to the present disclosure may be replaced with a base station.In this case, a configuration may be such that, the function included inthe above-described user terminal 20 may be included in the userequipment 20.

The term “connected” or “coupled” or any variation thereof means anydirect or indirect connection or connection between two or more elementsand may include the presence of one or more intermediate elementsbetween two elements “connected” or “coupled” with each other. Thecoupling or connection between the elements may be physical, logical, ora combination of these. For example, “connection” may be replaced with“access.” As used in the present disclosure, the two elements may beconsidered as being “connected” or “coupled” to each other using atleast one of the one or more wires, cables, and printed electricalconnections and, as a number of non-limiting and non-inclusive examples,electromagnetic energy having wavelengths in the radio frequency region,the microwave region, and the light (both visible and invisible) region.

The reference signal may be abbreviated as RS (Reference Signal) or maybe referred to as a pilot, depending on the standards applied.

As used in this disclosure, the expression “based on” does not mean“based on only” unless otherwise specified. In other words, theexpression “based on” means both “based on only” and “at least basedon.”

As long as “include,” “including,” and variations thereof are used inthis disclosure, the terms are intended to be inclusive in a mannersimilar to the term “comprising.” Furthermore, the term “or” used in thedisclosure is intended not to be an exclusive OR.

In the present disclosure, for example, if an article is added bytranslation, such as a, an, and the in English, the present disclosuremay include that the noun following the article is plural.

In the present disclosure, the term “A and B are different” may implythat “A and B are different from each other.” Note that the term mayalso imply “each of A and B is different from C.” The terms, such as“separated” or “coupled,” may also be interpreted similarly.

While the present invention is described in detail above, those skilledin the art will appreciate that the present invention is not limited tothe embodiments described in the present specification. The presentinvention may be implemented as modifications and variations withoutdeparting from the gist and scope of the present invention as defined byclaims. Accordingly, the description of the present specification is forillustrative purposes only and is not intended to have any restrictivemeaning with respect to the present invention.

LIST OF REFERENCE SYMBOLS

10 base station

110 transmitting unit

120 receiving unit

130 control unit

20 user equipment

210 transmitting unit

220 receiving unit

230 control unit

1001 processor

1002 storage device

1003 auxiliary storage device

1004 communication device

1005 input device

1006 output device

1.-5. (Canceled)
 6. A terminal comprising: a transmitting unit thattransmits a result of a measurement of a secondary cell; and a controlunit that determines, when the terminal transmits the result of themeasurement in a predetermined time period that is set according to apower class of the terminal, that the secondary cell is a known cell. 7.The terminal according to claim 6, wherein, when the terminal transmitsthe result of the measurement in the predetermined time period, and whena measured synchronization signal remains detectable according to a cellidentification condition during a constant time period from transmittingthe result of the measurement, the control unit determines that thesecondary cell is known.
 8. The terminal according to claim 6, furthercomprising: a receiving unit that receives a signal to activate thesecondary cell, wherein, when the terminal transmits the result of themeasurement in the predetermined time period, the control unit usespreviously obtained information on the secondary cell for activation ofthe secondary cell.
 9. The terminal according to claim 6, wherein, whenthe power class of the terminal is a power class of a radio device thatis intended for fixed use, the control unit sets the predetermined timeperiod to be longer than a predetermined time period for another powerclass.
 10. The terminal according to claim 6, wherein the result of themeasurement is an L3-RSRP measurement report.
 11. A communication systemcomprising: a terminal including a transmitting unit that transmits aresult of a measurement of a secondary cell to a base station, and acontrol unit that determines, when the terminal transmits the result ofthe measurement in a predetermined time period that is set according toa power class of the terminal, that the secondary cell is a known cell;and the base station that receives, from the terminal, the result of themeasurement of the secondary cell.
 12. A communication method executedby a terminal, the method comprising: transmitting a result of ameasurement of a secondary cell to a base station, and determining, whenthe terminal transmits the result of the measurement in a predeterminedtime period that is set according to a power class of the terminal, thatthe secondary cell is a known cell.